Relevance. The search and development of modern non-invasive methods for early periodontal disease detection are of scientific and practical value for a personalized approach to disease course prognosis and explaining the choice of treatment tactics. Morphological immaturity, high intensity of anabolic processes, functional failure of neurohumoral, endocrine and immunological defence systems combined with an imbalance between the synthesis and degradation of extracellular matrix components in children with undifferentiated connective tissue disease (UCTD) significantly in-creases the risk of developing periodontal diseases. The available data on the activity of salivary matrix metalloproteinases (MMPs), which play a leading role in regulating connective tissue protein metabolism and bone remodelling mechanisms in children with UCTD of various degrees, are scarce and require further study.Purpose. The study aimed to explain the clinical, diagnostic and prognostic value of MMPs as markers of inflammatory periodontal diseases in children with UCTD and dysplastic disorders of various severity.Material and methods. The study included 67 children with UCTD (main group) and 34 children of health groups I and II (comparison group) aged 12-17. The UCTD severity was established according to the diagnostic criteria by L. N. Abbakumova (2006) and a scale for assessing the significance of phenotypic and visceral signs. The main group was divided into two subgroups: Subgroup 1 (n = 38) – children with mild and moderate UCTD; Subgroup 2 (n=29) – children with severe UCTD. The studied groups had their periodontal status assessed, as well as the concentration of MMP-1, MMP-2, MMP-8, MMP-9 and their tissue inhibitors (TIMP-1, TIMP-2) in the oral fluid identified using the enzyme immunoassay, along with calculation done for the MMP ⁄ TIMP coefficients that set a balance between the degradation and synthesis of collagen.Results. The children with phenotypic signs of UCTD in the oral fluid appeared to show a statistically significant increase in the MMP-1, MMP-2, MMP-8, and MMP-9 levels and an imbalanced ratio in MMP-1⁄TIMP-1, MMP-2⁄TIMP-2, MMP-8⁄TIMP-1, MMP-9⁄TIMP-1, compared with health groups I, II. An increase in the MMP-1, MMP-2, and MMP-8 concentrations, along with dominating expression of MMP-9 over TIMP-1 in the oral fluid of children of Subgroup 2, causes an increase in intensity and prevalence of periodontal diseases compared to the patients in Sub-group 1 and comparison group.Conclusion. Thus, when children with UCTD don’t demonstrate an increase in specific tissue inhibitors TIMP-1 and TIMP-2 in their oral fluid, along with an increase in the levels of the respective matrixins is the key pathogenetic factor in the degradation of extracellular matrix proteins, which causes a depressing impact on the proliferative activity in the periodontal set of tissues.
